Method of softening textile material and resulting product



United States Patent METHOD OF SOFTTENING TEXTILE MATERIAL AND RESULTING PRODUCT Joseph J. Carnes, Greenwich, Conn., assignor to American Cyanamid Company, New York, N. Y., a corporation of Maine No Drawing. Application April 6, 1953, Serial No. 347,169

4 Claims. c1. 117-1395 This invention relates to a class of polymeric compounds which have outstanding characteristics as nonyellowing softening agents for cotton and rayon textiles during hot-finishing treatments and subsequent storage thereof. More particularly, the invention relates to a class of sulfosuccinic acid polyesters of either dihydroxyalkylamides or ethylene oxide condensation products thereof possessing softening properties, heat stability and other desirable characteristics.

In the course of their manufacture and finishing, cotton and rayon textiles are usually subjected to various heat treatments. Often, the textiles are treated with filters such as starch, gum tragacanth, gum ghatti, dextrines, and the like, in order to impart body to the cloth. These treatments, however, often result in the production of a relatively stiflf fabric which is harsh-feeling and less desirable commercially than fabrics having a soft hand.

Consequently, the industry has resorted to the use of several types of compounds for the softening of the finished fabric and, in the case of rayon textiles, for imparting increased lubricity thereto. Among the compounds employed by the art have been sulfonated hydrocarbons, waxes, stearates, sulfated oils, such as cottonseed oil, peanut oil, and similar sulfonated or sulfated oil products. In view of the economics involved in textile manufacture, some of the most widely-employed softening agents have been sulfated and/ or sulfonated tallow, sulfated and/or sulfonated monoand diglycerides of tallow, cottonseed oil, coconut oil and others containing the relatively long carbon chain fatty acids.

However, the incorporation of even small amounts of these agents in cotton and rayon textiles has frequently resulted in the undesirable yellowing of the fabric subsequent to the finishing thereof. This is primarily due to the fact that the washed and/or sized fabric is ordinarily dried at temperatures of about 250400 F. and is then immediately rolled into bolts. The inner layers of the bolted cloth retain the heat for a period of several days during which time these sulfated or sulfonated softening agents, all of which are relatively sensitive to heat, deteriorate sufliciently to cause serious yellowing of the treated fabric. Similarly, in the fabrication of garments from the treated textile materials, the cloth is frequently subjected to hot-pressing operations which cause these softening agents to deteriorate. Therefore, although sulfated and sulfonated fatty acids and fatty acid glycerides are recognized as acceptable textile softening agents, their lack of heat stability has rendered them undesirable for many textile finishing operations.

A principal purpose of the present invention is to provide a heat-stable, non-yellowing softening agent for cotton and rayon textiles during hot-finishing treatments and during subsequent storage thereof.

Other purposes, as well as features and advantages, of the present invention will become apparent from a consideration of the following specification wherein I have set forth a preferred embodiment of my inventive concept which is to be considered illustrative but not limitative of my invention.

1 have discovered that the members of a new class of polyesters of sulfosuccinic acid, and either dihydroxyalkylamides or ethylene oxide condensation products of such amides, possess outstanding textile softening properties without any appreciable tendency either to deteriorate under the influence of heat, or to cause any shade changes in the fabrics to which they are applied. In addition to these desirable qualities, this class of polymeric compounds has also been found to plasticize the starch sizes employed by the textile industry. Thus, the novel class of compounds of this invention provides the textile industry with a dual-purpose agent which acts both as a non-yellowing textile softening compound and a plasticizer for starch-sized fabrics.

A further important advantage of the invention resides in the fact that substantially all of the starting materials of these polyesters of sulfosucccinic acid are readily available commercially at relatively low cost, which renders the agents obtained extremely attractive to the manufacturers of textiles.

The novel class of heat-stable, non-yellowing textile softening agents of the invention has the following general polymeric formula:

wherein Me is a salt-forming cation, derived from any of the alkali metals, ammonium or other bases; n is the degree of polymerization and is an integer from 2 to about 12; and R is the residue of a dihydroxyalkylamide or an ethylene oxide condensation product thereof.

In order to define more properly the scope of the term residue of a dihydroxyalkylamide, the following generic structural formula is given as illustrative of the dihydroxyalkylamides from which the residues are derived by removal of the two hydroxy radicals. The formula is:

wherein R1 is an alkyl or alkenyl radical having from about 5 to about 22 carbon atoms; R2 is hydroxyalkyl or hydrogen; and R3 is hydroxyalkyl when R2 is hydroxyalkyl and is dihydroxyalkyl when R2 is hydrogen.

A consideration of the preceding definition therefore reveals the community of properties existing due to the presence in the dihydroxalkylamide of an alkylor alkenyl-substituted amide group RCON= and two hydroxy groups capable of condensing in the linear polymerization to be described hereinafter.

Briefly, the polyesters of the present invention are prepared by reacting a fatty acid with a suitable dihydroxyalkylamine to obtain the corresponding dihydroxyalkylamide. This amide is then polyesterified by heating under the proper temperature and pressure conditions for the required period of time with maleic an hydride (or its equivalent such as maleic acid or fumaric acid) to form the polymaleate of the amide. This polymeric esterification is continued under the required reaction conditions until the desired or necessary number of ester units have united. The polymaleate is then sulfonated to form the polysulfosuccinate of the dihydroxyalkylamide. Preferably, the sulfonation is carried out by heating the polyester with an aqueous solution of an alkali metal or ammonium bisulfite or metabisulfite to obtain the corresponding salt.

Salts of other bases may be obtained readily by first acidifying an alcoholic solution of the alkali metal or ammonium salt, whereby the free polyester of the sul- 3 fosuccinic acid is obtained, filtering off the inorganic salt of the acid used and reacting the free polyester with the desired base. Although they are not ordinarily employed in textile finishing treatments, salts of the polyvalent metals such as calcium, barium, zinc, lead, cadmium, and the like may be prepared, if desired, by adding stoichiometric quantities of their-oxides or hydroxides to the alcoholic polymeric ester solution, followed by stirring until the salt formation is complete. Salts of organic bases'such as methyl, ethyl, or butyl amine; guanylures; guanidine; hydroxyethylguanidine; biguanide; ethanolamine; triethanolamine; or higher aliphatic amines; aromatic amines; andheterocyclic bases such as nicotine, pyridine, quinoline, and alkaloids may be prepared by this method, as well as by direct sulfonatior' employing the sulfites and bisulfites of the organic bases.

' In general, the polyesters of sulfosuccinic acid range from viscous liquids to hard waxy compositions dependabout 12 ester units possess the desirable textile softening characteristics. All of these'products are di'spersible in water and some of them are also soluble in hydrocarbon solvents. The corresponding monomeric sulfosuccinates (in which It would be 1) are generally unsatisfactory as textile softeners due to their heat instability, whereas the corresponding polyesters containing in excess of an average of 12 ester units are generally insufficiently dispersible or soluble to permit their use in textile treatments.

A convenient method of following the course of the polymerization reaction and the value of n-exists in the determination of the acid number of the polyester, as expressed in ml. of KOH'required to'exactly neutralize 1 g. of product. The acid number decreases as'the polymerization progresses. For example, an acid'number of about 40 will indicate that the product contains an average ester unit content of about 1.5 to about 2, While an acid number of about -10 indicates an average ester unit content of 6 to 10,"depending on the molecular weight of the dihydroxylalkylamide employed.

The fatty acids which have been found suitable for preparing the products of the present invention have the general formula RICOOH wherein R1 represents an alkyl or alkenyl radical in which the number of carbon atoms is limited only by the commercial availability and cost of the particular fatty acid. The preferred range for the fatty acids applicable for the textile purposes of the present invention has been established to be from about 5 or 7 carbon atoms up to about 18 or '22 carbon atoms, although fatty acids having more or less carbon atoms are also suitable. Representative acids would include: stearic acid, lauric acid, palmitic acid, myristic acid, capric acid, behenic acid, arachidic acid, caprylic acid, caproic acid, valeric acid, butyric acid or other saturated fatty acids; oleic acid, ricinoleic acid, palmitoleic acid, pentenic acids, hexenic acids, sorbic acid, linoleic acid, decylenic acid, dodecylenic acid, or other unsaturated fatty acids.

Among the dihydroxyalkylamines suitable for'reacting with the above-mentioned fatty acids are: diethanolamine; a-glycerol amine; b-glycerol amine; diisopropanolamine; dipropanolamine; etc.

The fatty acid and the dihydroxyalkylamine may be reacted in substantially equimolecular quantities, or with as much as 10% excess either way. Reaction temperatures range from about 129 C. up to about 190 C., dependent upon the nature of' the particular reactants. The dihydroxyalkylamide obtained is usually a waxy-solid product varying in color from white to yellow, light-tan or brown.

The dihydroxyalkylamide may, if desired, be condensed with ethylene oxide, or an equivalent thereof, in the presence of a catalyst, such as sodium hydroxide, to form a polyglycolamide derivative which may be used in further reactions in somewhat similar fashion to the dihydroxyalkylamide. The dihydroxyalkylamide and the ethylene oxide may be condensed in various molar proportions up to as high as 1:50 or-even 1:100 o'r-more, but a ratio of approximately 1:6 has been. found preferable when textile agents are desired.

These polyglycolamide derivatives may be polyesterified by heating for a long enough time at a proper pressure with maleic anhydride, or its equivalent, and then sulfonated to yield products having the following polymeric formula (when the initial reactants were a fatty acid and diethanolamine):

SO3M8 11:

I' i it til Wherein R1, Me and ,n have meanings as previously stated.

The invention will be further illustrated in greater detail by the following specific examples. It should be understood,;however, that although these, examples may describe in particular detail some of the more specific features of the-present invention they are given primarily for purposes of illustration and the invention in its broader aspects is not to be construed aslimited thereto;

EXAMPLE I The preparation of the 'polysulfosuccinate ester of diethanolstearamide involved three steps. First, diethanolstearamide (N,N- bis-(2-hydroxyethy l) stearamide) is made by reacting stearicacid with diethanolamine. In step two, the diethanolstearamide is esterified with maleic anhydride in order to derive the polymeric alkyd. in step three, this alkyd is then sulfonated with sodiumbisulfite to yield the desired polysulfosuccinate ester.

Step I-Preparfati0n of diethanolstearamide 239 grams (0.85 mole) of stearic acid was reacted with 101 grams (0.94 mole) of diethanolamine at term peratures of approximately 154l 84 C. under-'an'inert atmosphere of carbon dioxide. The temperature was held within the above-indicated range for about 2.3 hours and approximately 23.0 ml. of water were collectedduring that time in a Barrett moisture collector. Approximately 8.7% of the diethanolamine remained 'unreacted.

The diethanolstearamideitself was a light cream wax.

After completion of the reaction, a titration showed the presence of approximately 5.0% basic impurities which may be removed by washing the diethanolstearamide with an acid such as hydrochloric or the like, followed by a neutralization with sodium carbonate. A yield of 172 grams (52%) was determined. The final product was a white solid wax.

In another instance, the preparation of the diethanolstearamide was carried out in the presence of an inert solvent, such as xylene, at a temperature of 130150 C. The developed water was collected in a Barrett moisture collector during the reaction which required between 6 to 16 hours, at the end of which time 4.5 to 7.0% basic impurities were present. The impurities were removed as above-described and the rest of the preparation continued as described below.

Step II (A)The preparation of the polymaleate of diethanolstearamide C11HasC=O The polymaleate of diethanolstearamide is prepared by was passed through a trap into the reaction mixture held at a temperature of 120-130 C. The condensation of the ethylene oxide was slow at first, but proceeded more readily after a few moles of ethylene oxide had been added. The sodium hydroxide catalyst was neutralized with hydrochloric acid. The amount of ethylene oxide added to the diethanolsteararnide was determined by weighing the flask before and after the addition of the gas. The product was a dark brown rubbery wax.

The polymaleate of the diethanolstearamide-ethylene oxide condensate may then be prepared by reacting the condensate with maleic anhydride in substantially equimolecular quantities at 130-165 C. for about 32 to 36 hours under an inert atmosphere of nitrogen. An inert solvent and a catalyst may be employed, if desired. Water was collected, as usual, the chain length was indieated to be 6.4 to 6.7 units by the acid number which was 11.5 to 12.3. The product was a tan to dark-brown brittle wax obtained in approximately 90% yield and was suitable for preparation of the polysulfosuccinate, ester as set forth in Step III following. I

Step lII.Sulf0nalion of the alkyds of diethanolstearamide OnHasC=O C17H35C=O 2H[OCH2CH2NCH2CH2OOCCH=CHCO]OH Nazszoi H2O 211 OCHzCHzNCHzCHzOOCCHCHICO CNS esterifying the diethanolstearamide with maleic anhydride or its equivalent. A p-toluenesulfonic acid catalyst may be employed and the esterification may take place, if desired, in the presence of an inert solvent such as xylene, but better results have occasionally been obtained without such additions.

172 grams (0.46 mole in 5% excess) of diethanolstearamide and 46.4 grams (0.48 mole) of maleic anhydride were charged into a one-liter flask equipped with a stirrer, condenser with water trap, and thermometer and refluxed at 165180 C. under an inert atmosphere of carbon dioxide. 2.0 ml. water were collected in the Barrett moisture collector during the 10-hour reaction time. A chain length of 4.2 units was indicated by the acid number which was 28.2. The product was a darkbrown wax obtained in the amount of 182 grams (84% yield).

The preceding esterification was also carried out in the presence of an inert solvent such as toluene (150 ml.) and 5.0 grams of p-toluenesulfonic acid catalyst and the refluxing temperature was held at 125 C. for 23 hours. The chain length of the sample at the end of that time was 2.5 units. The toluene was distilled ofi'under vacuum. The product was a tan wax obtained in 100% yield. When xylene was used as the inert solvent, the chain length was approximately 2.7 units.

Step II (B).Prepamtion of the polymaleate of the diethanolstearamide-ethylene oxide condensation product A condensation product of diethanolstearamide and ethylene oxide was prepared as an alternative compound to the diethanolstearamide to be used in the later prep- The stearamide and the sodium hydroxide catalyst were charged into a flask equipped with a stirrer,*ice-cooled condenser, thermometer and gas inlet. Ethylene oxide lengths'of 2.5 units were completely sulfonated at the.

end of 1722 hours. The excess bisulfite was oxidized with hydrogen peroxide and the product filtered. The poly'sulfosuccinates were neutralized to a pH of 6.5 with sodium hydroxide and evaporated to dryness on the steam bath and in a forced draft steam oven or left as a paste. The product was a brittle, tan wax or a thick, tan paste containing approximately 25% solids.

EXAMPLE 2 Preparation of the sulfosuccinate polyester of diethanollauramide L to... .I.

Diethanollauramide (N,N-bis- (2-hydroxyethyl)stearamide) was prepared by refluxing lauric acid with a 1% excess of diethanolamine in xylene until water ceased distilling from the reaction mixture. The xylene was then removed from the amide by distillation under reduced. pressure up to a temperature of 150 C. h A mixture of 34.2 g. (0.349 mole) of maleic anhydride, g. (0.349 mole|5% excess) of diethanollauramide, 175 ml. of toluene, and 5 g. of p-toluenesulfonic acid was refluxed for seventeen hours at -1 15 C., removing the water formed in a trap. The toluene was distilled 0115 under vacuum, leaving the polymaleate ester as a brown brittle waxy solid. The yield was 131 g., and the ester had an acid number of 37.2 indicating an, average chain length of 4.1 ester units.

This-polyester was mixed with 75.5 g. (0.349 mole-F 10% excess) of sodium met-abisulfite, 200 ml. of ethanol, and 200 ml. of water, and the mixture was refluxed with agitation for twenty-eight hours. It was treated with suflicient 30% hydrogen peroxide to oxidize the excess bisulfite,-stirred with Hyflo, and filtered. The pH was adjusted to -approximately 6.5 with sodium hydroxide and the solution was evaporated on the steam bath. After drying at 100 C. the product was obtained as a brown --O CHzCHzNCHaCHrO O CCH=CHC O OCH2CH2NCH2CH2O C CHCHzC O A solution of 157.5 g. (0.404 mole-16% excess) of diethanolsteararnide (prepared by the same procedure used for'diethanollauramide), 39.6 g.'(0.404 mole) of maleic anhydride, and 5 g. of p-toluenesulfonic acid in 150 ml. of toluene was refluxed at 120-125 C. for

twenty-four hours. After the first twenty hours, 65% of the theoretical amount of water was collected in the trap and no more distilled out. After distilling off the toluene under reduced pressure, titration of a sample of the maleate polyester indicated an average chain length of 2.5 ester units. The yield was 196 g. of brown wax.

This polyester, 192 g. (0.426 mole), was mixed with 87g. (0.457 mole) of sodium-metabisulfite, 200 ml. of ethanol and 200 ml. of water and the mixture was refluxed with agitation for twenty-two hours. Iodometric titration of the excess 'bisulfite indicated the sulfonation was complete. Another 200 ml. of water and 100 ml. of ethanol was added andthe excess bisulfite was oxidized with hydrogen peroxide. On cooling, it formed a light'tan paste containing 24% solids.

EXAMPLE 4 The following example illustrates the use of 2,3-dihydroxypropylamine and stearic acid in the preparation of the polyester of sulfosuccinic acid:

Step I.Preparati0n 0] the dihydroxyalkylamide CHINH2 C'HzNHO 0 011B CHOH 01111350 OOH CHOH H onion CHQOH REACTANTS 2,3-dihydr0xy propylamine- 47.5 g. of 95% purity..- 0.5 mole.

Ste'aric acid 142 g 0.55 mole by titration.

Xylene 75 mls.

Step II.-P0lyesterification of the=-dihydroxyalkylamide ornNnooonn CHCOOH $11011 HO O C CH CHQOH CHiNHC O CitHzs mat. LHzQ o oH'- onco'-n ii ii in REACTANTS [Product from Step I (l-stearamido 2,3-propanediol)] ir i i i giiiiiIIiIilljiIIIIIIIIIIIIIIIII 35.525133:

The equipment comprised a 500 ml., 3-neck flask, equipped with a thermometer, nitrogen inlet tube, stirrer, water trap and condenser. The reactants were refluxed for approximately 3 hours in which time a gel was formed. 12 mls. ofwater were distilled off during this reaction. Titration gave an acid number of 17 and a value for n of 7.4. 7

aOH

CHQN'HC 0 (3111135 H o OH 1 LC IHOCCHzCHCO 0Na 0 S OkNaJn REACTANTS [Polyester prepared in Step II (acid number-17), 161 g.]

Na2SO3,'6.3 g. (98% pure) Na2SaO5,'28.0 g.

160 mls. benzene 150 this. alcohol 150.rnls. water The equipment comprised a 1-liter, 3-neck flask equipped with a stirrer, thermometer and reflux condenser. The reactants were refluxed on a steam bath for about 1 3 hours at approximately 65 C. 250 mls. of solvent was stripped to raise the reflux temperature to approximately 75 C. and then 250 mls. of a 1:1

' mixture-of alcohol and water added.

ing, 48%;sulfonation by'titration was indicated. The

) unreacted bisulfite was oxidized to bisulfate with 235 mls. of 30% H202 and the bisulfate was neutralized to sulfate with 25% INaOI-I. The product was diluted with 500 -rnls. alcohol and 500 mls. benzene; Hyflo was added and the product was filtered by suction. The filtrate was then evaporated on a steam bath.

In employing the novel polyesters of the invention in textile softening treatments, a dispersion from about 0.25% to about 3% or more of the selected polyester is prepared in a water bath or, if the textile is to be sized at the same time, in an aqueous size bath. The textile material is thereafter impregnated in the bath up to a wet pickup of substantially of the weight of fabric and then dried according to normal operating procedures. Ordinarily, whereno sizing agent is employed, itis unnecessary tohave more than about 1% of thesoftening agent on the fabric in order to obtain the desired softness of hand in the .product. On the other hand, where a'sizing'agent is used,-it is sometimes necessary to increase thesoftening agent content to about 3% or more to obtain the desired improvement in softness of hand in the treated fabric.

Testing of the non-yellowing softening agents of the present invention revealed that they possessed the following advantages. No serious yellowing was produced in fabrics when they were heated at 95 C. for three days. The use of these agents did not cause any shade changes nor did they decrease the light fastness of dyes on the tested fabrics. These agents were easily dispersible liquids or pastes and were further found to soften or plasticize starch finishes.

Other uses for the novel compounds of the present invention would include emulsifying agents for any purpose, such as the lubrication of textile materials with mineral oils; fat-liquoring of leather; preparation of in secticidal sprays; emulsion polymerization processes; detergents; flotation of ores and minerals; dispersing agents, e. g. or pigments; demulsifying agents; scouring of wool; dyeing assistants; softening of paper hand towels; etc.

Although I have described but a few specific examples of my inventive concept, I consider the same not to be limited thereby nor to the specific substances mentioned therein, but to include various other compounds of equivalent constitution as set forth in the claims appended hereto. It is to be understood, of course, that any suitable changes, modifications and variations may be made without departing from the scope and spirit of the invention.

I claim:

1. A method of softening textile material which comprises impregnating the textile material with an aqueous dispersion of a polymeric sulfosuccinate ester of a fatty acid dihydroxyalkylamide, said ester having at least two but not more than about twelve ester units and said fatty acid containing more than 7 carbon atoms.

2. A method as defined in claim 1 in which the aqueous dispersion contains from about 0.25% to about 3% by weight of the polymeric ester.

3. A method as defined in claim 2 in which the pickup of aqueous dispersion by the textile material is substantially of the weight of the fabric.

4. A textile material characterized by improved softness of hand and having distributed therethrough from about 0.25% to about 3% by weight of a polymeric sulfosuccinate ester of a fatty acid dihydroxyalkylamide, said polymeric ester having at least two but not more than about twelve ester units and said fatty acid containing more than 7 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS 2,002,613 Orthner et a1 May 28, 1935 2,236,528 Epstein et a1. Apr. 1, 1941 2,637,663 Thurston May 5, 1953 OTHER REFERENCES Chemical Abstracts, 3111359, DAlelio et al., Three Series of N-substituted Aliphatic Amides. 

1. A METHOD OF SOFTENING TEXTILE MATERIAL WHICH COMPRISES IMPREGNATING THE TEXTILE MATERIAL WITH AN AQUEOUS DISPERSION OF A POLYMERIC SULFOSUCCINATE ESTER OF A FATTY ACID DIHYDROXYALKYLAMIDE, SAID ESTER HAVING AT LEAST TWO BUT NOT MORE THAN ABOUT TWELVE ESTER UNITS AND SAID FATTY ACID CONTAINING MORE THAN 7 CARBON ATOMS. 